Such an apparatus is therefore capable of replacing three apparatuses, namely: a circuit-breaker, and an upstream section switch and a downstream section switch associated therewith. This is particularly advantageous for an operator both because of the saving achieved in investment (lower costs, lower ground area requirement) and because of savings in maintenance while the apparatus is in operation.
The principle of such apparatus has been described in French patent No. 1 533 266, but no industrial implementation has been described in detail.
Progress achieved in the field of current interruption using sulfur hexafluoride (SF.sub.6) now makes it possible to envisage implementing such apparatus industrially, thereby making it possible:
to reduce the bulk of the apparatus; PA1 to reduce the energy required by its control box; and PA1 to reduce the cost price thereof.
An object of the present invention is thus to define a sulfur hexafluoride isolating circuit-breaker of the above-specified type which is compact in structure and which can easily be used in implementing a prefabricated substation.
Another object of the invention is to define a substation that is cheaper than substations of known type.
Another object of the invention is to provide an isolating circuit-breaker suitable for remote control both of its section switch function and of its circuit-breaker function.
Another object of the invention is to provide an isolating circuit-breaker that includes protection without using an auxiliary energy source.
The prior art is also illustrated by German petty patent number 1 870 065 which discloses a circuit-breaker whose poles are disposed on a horizontal bar capable of pivoting about its axis and of providing a section-isolating function for the circuit-breaker. When the circuit-breaker is in its isolating position, its poles are inclined, thereby reducing its isolation distance, and thus requiring the apparatus to be overdimensioned in order to obtain dielectric strength.
Another drawback of that device is that in its isolating position, its poles are at a potential that is not determined (floating potential).
Another drawback of the circuit-breaker described in the above-mentioned document is the need to use an insulating plate to insulate the front face of the apparatus when the circuit breaker is extracted.
Another drawback is that in the event of excess voltage between a set of busbars and cables, the gap between said elements maybe bridged by an arc.
Another drawback is that the poles of the circuit-breaker are necessarily controlled by rotary means and cannot be controlled by a push-pull action.
Another drawback is that the poles must be provided with connectors for making connection with the busbars or with the cables, and this excludes any direct engagement.
An object of the invention is to provide an isolating circuit-breaker that avoids the above-mentioned drawbacks.